To be quite frank. doing an oil change at 3 months is pretty much pointless. Even every 6 months unless the car is only used for short trips is also pointless.

Modern oils and modern engines do not have the same issues as older motors (and I am talking for an example of an old Holden 202). The crank case recalculation on new motors is much better with much less blow by etc

The only engines that need more attention are Diesels. Oil going off colour is certainly not meaning you have to change the oil as it is designed with all its additives to last the 15k or 12 months, I personally recommend 12 months OR 10k which ever comes first for petrol engines not used under extreme conditions such as short trips or heavy load.